Efficacy of Various Positive Reinforcers in the Treatment of Destructive Behavior Destructive behavior (e.g., self-injury, aggression) may impede the development of many individuals with disabilities. These behaviors may occur for many reasons however, for most individuals problem behaviors are controlled by social stimuli (e.g., access to attention, escape from aversive activities). One effective treatment for these behaviors is to no longer deliver the reinforcer (i.e., extinction) or to deliver the reinforcer contingent upon some alternative response (e.g., appropriate communication). Recent research has suggested that providing access to highly preferred alternative reinforcers (i.e., those that do not maintain problem behavior) is also an effective procedure for decreasing problem behavior. For example, an individual who engages in attention-maintained aggression might receive non-contingent access to a preferred toy rather than attention. Alternative reinforcers are typically determined using one of several different preference assessment procedures. However, recent research has suggested that existing preference assessments may not be the optimal method for identifying stimuli to be incorporated into behavioral interventions. Also, few investigations have examined the relative effectiveness of using alternative versus functional reinforcers in the treatment of destructive behavior. In this investigation, individuals with developmental disabilities will select their preferred items through a commonly used preference assessment. Next, a functional analysis will be conducted to identify the reinforcer that maintains destructive behavior (i.e., social positive reinforcement). In Experiment 1, we will compare the alternative reinforcer to the functional positive reinforcer by exposing both to progressive ratio (PR) schedules of reinforcement in which the number of responses required to access either reinforcer will increase progressively within the course of each session, such that the total response requirement increases as the session progressed. We will specifically compare which reinforcer (alternative or functional positive reinforcement) results in more responding under the PR schedules, which will serve as a measure of reinforcer potency. In Experiment 2, we will conduct a treatment evaluation in which the participants will receive access to either the alternative or the functional positive reinforcer contingent upon the omission of destructive behavior for a period of time. It is hypothesized that the reinforcer that is associated with more responding under the PR schedules (i.e., the high potency reinforcer) will also be associated with a greater reduction in problem behavior regardless of whether it was the functional or the alternative reinforcer. This research should extend our knowledge base in the treatment of destructive behavior by providing an alternative method of identifying effective interventions without necessitating a functional analysis. Destructive behavior (e.g., self-injury, aggression) negatively impact social and educational aspects of the lives of up to 50% of individuals with developmental disabilities including autism. These behaviors can be treated by delivering access to stimuli that maintain these behaviors or stimuli that are highly preferred (e.g., toys). The current study will compare how much work individuals will complete (under progressive ratio [PR] schedules of reinforcement) in order to access both those stimuli that produce their problem behavior as opposed to highly preferred stimuli. These two stimuli will then be compared within distinct treatments to reduce the occurrence of destructive behavior. It is anticipated that the stimulus associated with more work completion under the PR schedules will also be associated with a greater reduction in destructive behavior during treatment.